Quantitative Fit Tests of Selected Respirators for Health Care Workers Caring for Patients with Confirmed or Suspected COVID-19

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Thosporn Ekpreechakul
Wiphasiri Saiphiroonthong,MD
Warut Chaiwong
Chaiyos Kunanusont, MD, PhD


OBJECTIVES: The abrupt emergence of COVID-19 cases has raised demand for personal protective equipment (PPE). We compared fit factors of various masks and respirators available in healthcare settings in Thailand to assess suitability of sealed surgical mask or N95 respirator as an alternative to a surgical N95 respirator.

MATERIALS AND METHODS: A total of 31 quantitative respirator fit tests were performed among 3 masks and 5 respirators using PortaCount 8048, TSI Incorporated, Minnesota, USA, following Occupational Safety and Health Administration (OSHA) protocols.

RESULTS: Fit factors of two unsealed surgical masks were around 4 – 5. When they were sealed with 3M micropore tape, the fit factors increased to 33 – 38, which were below the OSHA criterion of 100. Fit factors of four unsealed masks and respirators were between 11 - 95, but after sealing, the fit factors increased to 199 and more. Two respirators passed the criterion of 100 without sealing.

CONCLUSIONS: Sealing of both masks and respirators improved fit factors substantively. Therefore, we recommend “always seal” masks and respirators particularly in the situation where an individual fit testing is not mandatorily required. To better protect healthcare workers caring for suspected or confirmed COVID-19 cases, it is advised that every healthcare worker should be trained on wearing an N95 respirator and go through a respirator fit test as part of respiratory protection program.


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Ekpreechakul T, Saiphiroonthong,MD W, Chaiwong W, Kunanusont, MD, PhD C. Quantitative Fit Tests of Selected Respirators for Health Care Workers Caring for Patients with Confirmed or Suspected COVID-19. BKK Med J [Internet]. 2020 Sep. 25 [cited 2022 Jul. 7];16(2):196. Available from: https://he02.tci-thaijo.org/index.php/bkkmedj/article/view/241348
Original Article


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